ECSim-2: A Performance Evaluator for Erasure Code based Storage Systems

In today's world, cloud storage systems built on distributed technology, are being used to store, manage and access massive amount of data in real time. The data replication based storage method is used by the storage service providers, to ensure fault tolerance although simple, results in storage overhead. With erasure code based storage systems, additional storage requirements to ensure fault tolerance can be reduced, while ensuring reliability equivalent to data replication. Several schemes of erasure coding existing today, however performance evaluation of such schemes through real distributed storage systems, is costly and time consuming. A feasible alternative solution for the problem is the use of simulators. In this research paper, we present a framework that simulates the behavior of an erasure code based storage system. This framework is implemented as an extension to CloudSim, thus making it a platform capable of performance evaluation of the erasure coding schemes. The simulator developed can measure the encoding, decoding delays, transmission delays and congestion. The simulator also has provisions for creating virtual storage nodes, fail the nodes and restore them as part of the testing of the erasure coded storage system.